1. Field of the Invention
The present invention relates to a fuel feed system for a vehicle having a fuel pump unit accommodated in a fuel tank, the fuel pump unit including a fuel pump and a fuel filter connected to a lower-end fuel suction portion of the fuel pump. Moreover, the present invention relates a vehicle with a fuel feed system.
2. Description of the Prior Art
The fuel tank of the fuel feed system for a vehicle has a restricted shape and volume by the shape and width of a space where the fuel tank should be disposed. Meanwhile, the fuel tank is required to have a volume as large as possible and the fuel pump unit must be easily attached therewith.
As to a mounting position of the fuel pump unit, in the case where a large space is easily ensured below the fuel tank, the fuel pump unit is frequently mounted upright from the bottom wall of the fuel tank. On the other hand, in the case where a large space is easily ensured above the fuel tank, the fuel pump unit is frequently mounted in a hanging manner from the upper wall of the fuel tank.
Conventionally, in the structure in which the fuel pump unit is mounted in the hanging manner from the upper wall of the fuel tank, the fuel filter connected to a lower-end fuel suction portion of the fuel pump is attached in an exposed state (naked state), and the fuel filter is disposed as close as possible to the bottom wall of the fuel tank such that fuel in the fuel tank is sucked substantially completely.
However, in the case where the vehicle jumps, the vehicle runs on an upward slope, a downward slope or in a slope land, or the vehicle accelerates or decelerates with a small fuel quantity remaining in the fuel tank, the fuel is undulated in the fuel tank or the fuel is moved to one side in a backward and forward direction or a right and left direction. Therefore, air (e.g. bubbles) is mixed into the fuel or the fuel filter is temporarily exposed to the air, which sometimes results in an air inhaling phenomenon of the fuel pump. Due to the air inhaling phenomenon, power efficiency of the fuel pomp will be reduced.
In a conventional vehicle fuel feed system shown in FIG. 16 (Specification of U.S. Patent Publication No. 2006/273572), a fuel filter 103 connected to a lower-end fuel suction portion 102 of a fuel pump 101 is covered with a filter housing 105 in order to prevent the air inhaling phenomenon caused by the movement or undulation of the fuel.
A detailed structure of the fuel feed system for the vehicle of FIG. 16 will be described below. A fuel pump unit 100 is accommodated in a fuel tank 110 and is supported in the hanging manner from an upper wall 111 of the fuel tank 110. The fuel filter 103 is formed in a flattened shape, and is connected to the lower-end fuel suction portion 102 while inclined with respect to a horizontal line. Then the fuel filter 103 is disposed near a bottom wall 112 of the fuel tank 110.
A lower side, backward and forward sides, and right and left sides of the fuel filter 103 are covered with the filter housing 105. The filter housing 105 is integrally formed with a circumferential side wall cover 107 of the fuel pump 101, and is connected to the circumferential side wall of the filter housing 105 without expanding the circumferential side wall cover 107 in the backward and forward directions and the right and left directions. Although not shown, one or plural fuel flow holes are formed in the filter housing 105, and the fuel is supplied from the fuel flow hole into the filter housing 105.
However, in the fuel feed system shown in FIG. 16, an area and a shape of the fuel filter 105 as seen from above is substantially restricted so as to fit into a region of the fuel pump 101 as seen from above, and the fuel filter 105 is attached in an inclined state with respect to the horizontal plane. Therefore, the following problems are generated.
(1) Since the shape of the fuel filter 103 as seen from above is restricted to the region of the fuel pump 101 as seen from above, even if the fuel filter 103 is supported in the inclined state, a suction area of the fuel filter soaking in the fuel cannot be largely increased, and clogging during use is easily generated to decrease a suction ratio in a short time.
(2) Since the fuel filter 105 is supported in the inclined state, the upper portion of the fuel filter 105 is exposed to the air to possibly generate the air inhaling phenomenon at an early stage in the case where the remaining fuel quantity becomes small.